Method and apparatus for transferring a tape by spooling

ABSTRACT

A method and apparatus for transferring a tape by spooling is disclosed. A tape is transferred by spooling from a first, unwinding spool onto a second, winding spool, both spools being driven via a drive as a function of a predefined tape tension and/or a predefined tape setpoint speed at a setpoint rotational speed and/or with a setpoint torque. The respective setpoint rotational speed and/or the respective setpoint torque being determined as a function of a geometrical mean of the winding circumferences of the two spools. The geometrical mean of the winding circumferences of the two spools is determined continuously during transfer by spooling.

This application claims the priority of German Patent Document No. 10 2005 024 091.7, filed May 25, 2005, the disclosure of which is expressly incorporated by reference herein.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a method for transferring a tape by spooling. Furthermore, the invention relates to an apparatus for transferring a tape by spooling.

During transfer of tapes by spooling, the object is often set of regulating or controlling the tape speed and the tape tension to a defined value. A setpoint rotational speed or a setpoint torque for the corresponding drives cannot be stipulated, however, as they change during the spooling process or transfer process of the tape on account of the changing diameters of the spools.

German Patent Document No. DE 44 27 780 C2 discloses a method for transferring a tape by spooling from a first, unwinding spool onto a second, winding spool, both spools being driven via in each case a drive as a function of a predefined tape tension and a predefined tape setpoint speed at a setpoint rotational speed and/or with a setpoint torque. According to DE 44 27 780 C2, the respective setpoint rotational speeds and the respective setpoint torques are determined as a function of a mathematical/geometrical mean of the winding circumferences of the two spools, it being presumed that the geometrical mean of the winding circumferences is constant. In order to determine the geometric mean of the winding circumferences, it is proposed according to DE 44 27 780 C2 to measure the current radii of the two spools once and to calculate the geometrical mean of the winding circumferences therefrom. This has the disadvantage that the current radii of both spools have to be measured. As an alternative, DE 44 27 780 C2 proposes determining the geometrical mean of the winding circumferences before the start of the transfer by spooling using the known starting radius of a spool and the rotational-speed ratio of the spools, which is measured during starting. Here, the measurement has to take place within a short time period, so that an inaccurate result can occur. Both variants have the disadvantage that a constant geometrical mean of the winding circumferences is presumed and therefore varying tape parameters in thickness and length which can occur during transfer by spooling or during a tape change cannot be allowed for.

Proceeding from this, the present invention is based on the problem of providing a novel method for transferring a tape by spooling and a corresponding apparatus.

This problem is solved by a method and apparatus for transferring a tape by spooling. According to the invention, the geometrical mean of the winding circumferences of the two spools is determined continuously during transfer by spooling.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred developments of the invention result from the following description. One exemplary embodiment of the invention is explained in greater detail using the drawing, without being restricted thereto. In the drawing:

FIG. 1 shows an apparatus for transferring a tape by spooling, in order to clarify the method according to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

In the following text, the present invention will be described in greater detail with reference to FIG. 1.

FIG. 1 shows an apparatus 10 for transferring a tape 12 which is wound on a first spool 11 by spooling onto a second spool 13. The first spool 11 is also called an unwinding spool and the second spool 13 is also called a winding spool. Both spools 11 and 13 are usually connected in each case via a shaft 14 and 15, respectively, to a motor 16 and 17, respectively, which drives the former. The rotational speeds of the motors 16 and 17 and therefore the rotational speeds of the spools 11 and 13 can be determined with the aid of sensors 18 and 19. The sensors 18, 19 can be configured as encoders. Instead of encoders, other sensors can also be used, for example tachometers, magnetic rotary encoders or else rotary encoders based on eddy current. According to FIG. 1, a rotational speed N₁₁ of the first, unwinding spool 11 can be measured with the sensor 18 and a rotational speed N₁₃ of the second, winding spool 13 can be measured with the sensor 19.

The first, unwinding spool 11 is characterized by a plurality of radii, namely by what is known as an empty radius r₁₁, what is known as a starting radius r_(11, START) and what is known as a current radius R₁₁. The second, winding spool 13 is likewise characterized by a plurality of radii, namely by what is known as an empty radius r₁₃, a starting radius r_(13, START) and a current radius R₁₃. The starting radii r_(11, START) and r_(13, START) are the radii of the spools 11, 13 which are present at the start of the transfer by spooling. The current radii R₁₁ and R₁₃ are radii of the spools 11, 13 which change during transfer by spooling. When the entire tape length is wound onto one of the spools 11 or 13, the latter then assumes the radius r_(11, VOLL) or r_(13, VOLL), respectively, whereas the respective other spool 13 or 11 then assumes the empty radius r₁₃ or r₁₁, respectively.

It is to be noted here that, apart from the exemplary embodiment described, it goes without saying that contactless sensing of the rotational speeds of the spools can take place within the context of the invention. The correlation of the motors and coils then takes place via corresponding transmission ratios, and the rotational-speed sensors can then also be arranged, for example, on the coils.

If the tape 12 is transferred by spooling only in one direction, the motor 16 or 17 of the unwinding shaft 14 or 15, respectively, can also be used as a brake.

In the context of the present invention, with the aid of the apparatus 10 which is shown in FIG. 1, the tape 12 which is wound on the first, unwinding spool 11 is then to be transferred by spooling onto the second, winding spool 13, a control or regulating device 20 generating setpoint rotational speeds and/or setpoint torques as actuating variables 21, 22 for the drives 16, 17 of the spools 11, 13 as a function of the measured rotational speeds N₁₁ and N₁₃ of the spools 11 and 13 and as a function of a predefined tape setpoint speed V_(BAND, SOLL) and/or a predefined tape tension F_(BAND, SOLL).

Here, in the context of the present invention, the setpoint rotational speeds and/or setpoint torques are generated as a function of a mathematical/geometrical mean UMG of the winding circumferences of the two spools 11 and 13, the geometrical mean UMG of the winding circumferences being determined or calculated continuously during the transfer by spooling, within the context of the present invention. The following is true for the mathematical/geometrical mean UMG of the winding circumferences: UMG=2*π*√{square root over (R ₁₁ ² +R ₁₃ ²)}

For the continuous determination of the geometrical mean UMG of the winding circumferences of the two spools 11, 13, the knowledge and/or measurement of the starting radius r_(13, START) of the winding spool 13 or the starting radius r_(11, START) of the unwinding spool 11 is required in addition to the measurement of the rotational speeds N₁₁, N₁₃ of the spools 11, 13. Using the following equations, the geometrical mean UMG of the winding circumferences of the two spools 11, 13 can be calculated from these variables, U₁₁ and U₁₃ being calculated revolutions of the drives 16, 17 since the start or beginning of the transfer by spooling at the instant t₀, and xwa representing the current rotational-speed ratio of the winding spool 13 with respect to the unwinding spool 11. U₁₁ = ∫_(t₀)^(t)N₁₁(t)  𝕕t U₁₃ = ∫_(t₀)^(t)N₁₃(t)  𝕕t ${xwa} = \frac{N_{13}(t)}{N_{11}(t)}$ ${UMG} = {2*\pi*r_{13,{START}}*\left( {U_{13}^{2} + U_{11}^{2}} \right)*\sqrt{\frac{{xwa}^{2} + 1}{\left( {U_{11}^{2} - U_{13}^{2} + {2*{xwa}*U_{11}*U_{13}}} \right)^{2}}}}$ ${UMG} = {2*\pi*r_{11,{START}}*\left( {U_{13}^{2} + U_{11}^{2}} \right)*\sqrt{\frac{{xwa}^{2} + 1}{\left( {U_{11}^{2} - U_{13}^{2} + {2*{xwa}*U_{11}*U_{13}}} \right)^{2}}}}$

The starting radii r_(11, START) and r_(13, START) can be converted into one another as follows (the calculation of the current radii can be represented in each case by corresponding transformation): $r_{11,{START}} = {r_{13,{START}}\frac{{2*U_{11}*U_{13}} + {{xwa}*\left( {U_{13}^{2} - U_{11}^{2}} \right)}}{{2*{xwa}*U_{11}*U_{13}} + U_{11}^{2} - U_{13}^{2}}}$

As has already been mentioned, the starting radius r_(13, START) of the winding spool 13 or the starting radius r_(11, START) of the unwinding spool 11 is required in order to calculate the geometrical mean UMG of the winding circumferences of the two spools 11, 13. This starting radius r_(13, START) of the winding spool 13 or the starting radius r_(11, START) of the unwinding spool 11 can either be predefined or determined by measurement during the transfer by spooling.

During the determination or calculation of the starting radius r_(13, START) of the winding spool 13, a measured tape speed V_(BAND) is used which is measured in the exemplary embodiment on a tape-guiding roller 23 with the aid of a sensor 24. It goes without saying that other measuring methods of the tape speed are conceivable which are carried out, for example, in a contactless or optical manner. The sensor 24 supplies the control or regulating device 20 with a rotational speed N₂₃ of the tape-guiding roller 23, from which the tape speed V_(BAND) of the tape 12 which is to be transferred by spooling and therefore the starting radius r_(13, START) of the winding spool 13 can be calculated, with specification of a radius r₂₃ of the tape-guiding roller 23, using the two following equations: $r_{13,{START}} = {v_{BAND}*\frac{\left( {{N_{11}*\left( {U_{11}^{2} - U_{13}^{2}} \right)} + {2*U_{11}*U_{13}*N_{13}}} \right)}{2*\pi*N_{11}*N_{13}*\left( {U_{11}^{2} + U_{13}^{2}} \right)}}$ v_(BAND) = 2 * π * N₂₃ * r₂₃

As an alternative, the measurement of the starting radius r_(13, START) of the winding spool can be determined on the basis of a tape length L_(BAND) which has been transferred by spooling since the start of the transfer by spooling at the instant t₀, it being possible for the tape length L_(BAND) which has been transferred by spooling since the start of the transfer by spooling to be calculated from the integral of the tape running speed V_(BAND). According to this alternative, the starting radius r_(13, START) of the winding spool 13 is then calculated using the two following equations: $r_{13,{START}} = {L_{BAND}*\frac{U_{11}^{2} - U_{13}^{2} + {2*{xwa}*U_{11}*U_{13}}}{2*\pi*U_{11}*U_{13}*\left( {U_{11} + {U_{13}*{xwa}}} \right)}}$ L_(BAND) = ∫_(t₀)^(t)v_(BAND)(t)  𝕕t = 2 * π * r₂₃ * ∫_(t₀)^(t)N₂₃(t)  𝕕t

With the aid of the geometric mean UMG of the winding circumferences of the spools 11, 13 which is determined continuously in the abovementioned manner, the setpoint rotational speeds N_(SOLL) and/or setpoint torques M_(SOLL) for the drives 16, 17 can then be determined using the two following equations, the setpoint rotational speeds and setpoint torques which are determined by the control or regulating device 20 being supplied to the drives 16, 17 as actuating variables 21 and 22, respectively: $N_{SOLL} = {\frac{v_{{BAND},{SOLL}}}{UMG}*\sqrt{1 + {xwa}^{2}}}$ $M_{SOLL} = \frac{F_{{BAND},{SOLL}}*{UMG}}{2*\pi*\sqrt{1 + \left( \frac{1}{xwa} \right)^{2}}}$

In the context of the present invention, further variables can be calculated; for example, the radius r_(11, VOLL) of the unwinding spool 11 using the following equation, the spool 11 assuming the radius r_(11, VOLL) when the entire tape 12 is wound completely onto the spool 11: $r_{11,{VOLL}} = \sqrt{\frac{{UMG}^{2}}{4*\pi^{2}} - r_{13}^{2}}$ $r_{11,{VOLL}} = \sqrt{\frac{r_{13,{START}}^{2}*\left( {U_{11}^{2} + U_{13}^{2}} \right)^{2}*\left( {{xwa}^{2} + 1} \right)}{\left( {U_{11}^{2} - U_{13}^{2} + {2*{xwa}*U_{11}*U_{13}}} \right)^{2}} - r_{13}^{2}}$

Furthermore, an overall winding cross-sectional area can be calculated from the two winding cross-sectional areas A₁₁, A₁₃ of the spools 11, 13 with the following equation: ${A_{11} + A_{13}} = \frac{{UMG}^{2}}{4*\pi}$

Moreover, in the context of the present invention, a tape thickness D of the tape 12 which is to be transferred by spooling can be determined with the following equation: $D = {2*r_{13,{START}}*\left( \frac{U_{13} - {{xwa}*U_{11}}}{U_{11}^{2} - U_{13}^{2} + {2*{xwa}*U_{11}*U_{13}}} \right)}$

Depending on the tape width, it is to be taken into consideration here that the thickness D which is calculated with the aid of the above equation can include any air inclusions between the individual winding layers. If the real nominal tape thickness is known or can be measured, the thickness of the air inclusions or their change in thickness can be determined with the method according to the invention as a consequence of the spooling transfer process.

The overall tape length L_(BAND, GESAMT) can likewise be calculated with the method according to the invention, to be precise on the basis of the following equation: $L_{{BAND},{GESAMT}} = {\pi*\frac{\left( {r_{11,{VOLL}}^{2} - r_{11}^{2}} \right)}{D}}$

Here, the free travel length of the tape 12 between the two spools 11 and 13 is to be added to the value which is determined with the aid of the above equation.

Furthermore, a changing speed of the rotational-speed ratios of the two spools 11 and 13 can be determined as follows: $\frac{\mathbb{d}{xwa}}{\mathbb{d}t} = {2*\frac{\left( {N_{11}^{2} + N_{13}^{2}} \right)*\left( {{U_{11}*N_{13}} - {U_{13}*N_{11}}} \right)}{N_{11}^{2}*\left( {U_{11}^{2} + U_{13}^{2}} \right)}}$

With the aid of the method according to the invention for transferring a tape by spooling between two spools, it is proposed for the first time to determine the mathematical/geometrical mean UMG continuously which is required to determine the setpoint rotational speeds and setpoint torques for the drives of the two spools. As a result, varying tape parameters in thickness and length which can occur during transfer by winding or during a tape change can be allowed for.

LIST OF DESIGNATIONS

10 Apparatus

11 Spool

12 Tape

13 Spool

14 Shaft

15 Shaft

16 Drive

17 Drive

18 Sensor

19 Sensor

20 Control and regulating device

21 Actuating signal

22 Actuating signal

23 Tape-guiding roller

24 Sensor

The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof. 

1. A method for transferring a tape by spooling from a first, unwinding spool (11) onto a second, winding spool (13), wherein both spools are driven via a respective drive as a function of a predefined tape tension and/or a predefined tape setpoint speed at a setpoint rotational speed and/or with a setpoint torque, and the respective setpoint rotational speed and/or the respective setpoint torque being determined as a function of a geometrical mean (UMG) of a winding circumference of each of the two spools, wherein the geometrical mean (UMG) of the winding circumferences of the two spools is determined continuously during transfer by spooling.
 2. The method according to claim 1, wherein, in order to determine the geometrical mean (UMG) of the winding circumferences of the two spools, a starting radius (r_(13, START)) of the winding spool is predefined and/or measured, and wherein actual rotational speeds (N₁₁, N₁₃) of the two spools (11, 13) are measured, and wherein the geometrical mean (UMG) of the winding circumferences of the two spools (11, 13) is calculated using the following equations: U₁₁ = ∫_(t₀)^(t)N₁₁(t)  𝕕t; U₁₃ = ∫_(t₀)^(t)N₁₃(t)  𝕕t; ${{xwa} = \frac{N_{13}(t)}{N_{11}(t)}};$ ${UMG} = {2*\pi*r_{13,{START}}*\left( {U_{13}^{2} + U_{11}^{2}} \right)*{\sqrt{\frac{{xwa}^{2} + 1}{\left( {U_{11}^{2} - U_{13}^{2} + {2*{xwa}*U_{11}*U_{13}}} \right)^{2}}}.}}$
 3. The method according to claim 1, wherein, in order to determine the geometrical mean (UMG) of the winding circumferences of the two spools (11, 13), a starting radius (r_(11, START)) of the unwinding spool (11) is predefined and/or measured, and wherein actual rotational speeds (N₁₁, N₁₃) of the two spools (11, 13) are measured, and wherein the geometrical mean (UMG) of the winding circumferences of the two spools (11, 13) is calculated using the following equations: U₁₁ = ∫_(t₀)^(t)N₁₁(t)  𝕕t; U₁₃ = ∫_(t₀)^(t)N₁₃(t)  𝕕t; ${{xwa} = \frac{N_{13}(t)}{N_{11}(t)}};$ ${UMG} = {2*\pi*r_{11,{START}}*\left( {U_{13}^{2} + U_{11}^{2}} \right)*{\sqrt{\frac{{xwa}^{2} + 1}{\left( {U_{11}^{2} - U_{13}^{2} + {2*{xwa}*U_{11}*U_{13}}} \right)^{2}}}.}}$
 4. The method according to claim 2, wherein the starting radius (r_(13, START)) of the winding spool (13) is predefined.
 5. The method according to claim 3, wherein the starting radius (r_(11, START)) of the unwinding spool (11) is predefined.
 6. The method according to claim 2, wherein a tape speed (V_(BAND)) is measured in order to measure the starting radius (r_(13, START)) of the winding spool (13), and wherein the starting radius (r_(13, START)) is calculated using the following equation: $r_{13,{START}} = {v_{BAND}*{\frac{\left( {{N_{11}*\left( {U_{11}^{2} - U_{13}^{2}} \right)} + {2*U_{11}*U_{13}*N_{13}}} \right)}{2*\pi*N_{11}*N_{13}*\left( {U_{11}^{2} + U_{13}^{2}} \right)}.}}$
 7. The method according to claim 5, wherein a rotational speed (N₂₃) of a tape-guiding roller (23) is measured in order to measure a tape speed (V_(BAND)), and wherein the tape speed (V_(BAND)) is calculated, with specification of a radius (r₂₃) of the tape-guiding roller (23), using the following equation: ν_(BAND)=2*π*N ₂₃ *r ₂₃.
 8. The method according to claim 2, wherein a tape length (L_(BAND)) which has been transferred by spooling since a start of a transfer is measured in order to measure the starting radius (r_(13, START)) of the winding spool (13), and wherein the starting radius (r_(13, START)) is calculated using the following equation: $r_{13,{START}} = {L_{BAND}*{\frac{U_{11}^{2} - U_{13}^{2} + {2*{xwa}*U_{11}*U_{13}}}{2*\pi*U_{11}*U_{13}*\left( {U_{11} + {U_{13}*{xwa}}} \right)}.}}$
 9. The method according to claim 7, wherein the rotational speed (N₂₃) of the tape-guiding roller (23) is measured in order to measure a tape length (L_(BAND)) which has been transferred by spooling since a start of a transfer, and wherein the tape length (L_(BAND)) which has been transferred by spooling is calculated, with specification of the radius (r₂₃) of the tape-guiding roller (23), using the following equation: L_(BAND) = ∫_(t₀)^(t)v_(BAND)(t)  𝕕t = 2 * π * r₂₃ * ∫_(t₀)^(t)N₂₃(t)  𝕕t.
 10. The method according to claim 1, wherein the setpoint rotational speeds (N_(SOLL)) of the spools (11, 13) are calculated from the predefined tape setpoint speed (V_(BAND, SOLL)) using the following equation: $N_{SOLL} = {\frac{v_{{BAND},{SOLL}}}{UMG}*{\sqrt{1 + {xwa}^{2}}.}}$
 11. The method according to claim 1, wherein the setpoint torques (M_(SOLL)) of the spools (11, 13) are calculated from the predefined tape tension (F_(BAND, SOLL)) using the following equation: $M_{SOLL} = {\frac{F_{{BAND},{SOLL}}*{UMG}}{2*\pi*\sqrt{1 + \left( \frac{1}{xwa} \right)^{2}}}.}$
 12. The method according to claim 1, wherein a changing speed of rotational-speed ratios of the two spools (11, 13) is determined as follows: $\frac{dxwa}{dt} = {2*{\frac{\left( {N_{11}^{2} + N_{13}^{2}} \right)*\left( {{{U_{11}*N_{13}} - U_{13}} \neq N_{11}} \right)}{N_{11}^{2}*\left( {U_{11}^{2} + U_{13}^{2}} \right)}.}}$
 13. An apparatus for transferring a tape by spooling from a first, unwinding spool (11) onto a second, winding spool (13), comprising a control or regulating device for carrying out the method according to claim
 1. 14. A method for transferring a tape by spooling from a first, unwinding spool onto a second, winding spool, comprising the steps of: driving the first and second spools by first and second drives, respectively, at a respective setpoint value, wherein the first and second spools have a respective winding circumference during a transfer process; wherein the respective setpoint value for each spool is determined as a function of a geometrical mean of the winding circumferences and wherein the geometrical mean is determined continuously during the transfer process.
 15. The method according to claim 14, wherein the setpoint value is a rotational speed.
 16. The method according to claim 14, wherein the setpoint value is a torque.
 17. An apparatus for transferring a tape, comprising: a first unwinding spool having a continuously changing tape winding circumference during a tape transfer process; a second winding spool having a continuously changing tape winding circumference during the tape transfer process; and a control device coupled to the first and second spools; wherein the control device provides a respective setpoint value to the first and second spools for driving the first and second spools during the tape transfer process and wherein the respective setpoint value for each spool is determined by the control device as a function of a geometrical mean of the tape winding circumferences of the first and second spools, and further wherein the geometrical mean is determined continuously during the transfer process.
 18. The apparatus according to claim 17, wherein the setpoint value is a rotational speed.
 19. The apparatus according to claim 17, wherein the setpoint value is a torque.
 20. The apparatus according to claim 17, wherein the respective setpoint values are a function of a predefined tape setpoint value. 